Compared with normal rigid substrates, flexible substrates have a wider range of applications due to bendability, ease for carriage, safety, and broad applications in consumer products. However, flexible substrates have a large coefficient of thermal expansion and poor resistance against heat, moisture, oxygen, and chemicals. Since typical flexible substrates cannot block the transmission of moisture and oxygen completely, electronic devices on the typical flexible substrates experience accelerated aging. Consequently, these short-lived electronic devices fail to fulfill commercial needs.
Generally speaking, the electronic device is disposed between two substrates, and the upper and lower substrates are closely attached to each other with a sealant so as to reduce contact of moisture and oxygen with the electronic device. However, moisture and oxygen may still permeate through the sealant and contact with the electronic device and thereby lower down the service life of the electronic device.